1. Field of the Invention
The invention relates generally to a nasal respiratory assembly for delivering a therapeutic treatment, medication and/or pressurized gas to a patient. More specifically, the invention relates to a nasal respiratory assembly comprising a mask and ventilator hose. The mask comprises intake ports, an exhaust port and one or more delivery ports. The nasal respiratory assembly is configured to prevent direct delivery of the therapeutic treatment, medication or pressurized gas into the patient's nasal cavities thereby providing a more comfortable and natural breathing pattern. In an exemplary embodiment, the nasal respiratory assembly configuration allows a medication to be delivered into the pressurized gas flow in close proximity to the patient's nasal cavities.
2. Prior Art
Continuous positive airway pressure or “CPAP” is a common method for ameliorating a variety of breathing disorders including respiratory failure, obstructive sleep apnea and some neuromuscular diseases in adults as well as respiratory distress syndrome and bronchopulmonary dysphasia in infants. CPAP respiratory assemblies typically include a mask connected to a ventilator through a ventilator hose. The ventilator provides a continuous source of pressurized air or other breathable gas using an electrically driven blower that is controlled by a servo and micro-controller unit. During use, the mask is affixed over the nasal passages to create a ventilation chamber and secured to the patient's head by one or more straps. The mask is usually made of a rigid or semi-rigid material and has a face-contacting surface including an intake port, which is aligned with the wearer's nasal cavities. The face-contacting surface is usually prepared of a flexible material that conforms to various facial contours. The straps are adjusted to secure the mask against the face with sufficient force to achieve a relatively gas tight seal.
However, there are numerous disadvantages associated with the use of CPAP ventilators. It has been recognized that the delivery of pressurized gases to the respiratory tract of a patient often results in discomfort, especially when treatment is for an extended period of time.
One primary disadvantage to standard nasal masks used in clinical settings is discomfort due to the speed and force of the pressurized gas being delivered into the nasal cavities. Patients often suffer from dried nasal cavities resulting in nosebleeds and unnatural breathing patterns that can result in coughing or gagging. In some cases, administration of positive pressure ventilation, either mechanical ventilation or non-invasive ventilation, can result in barotrauma (pressure-related injury) leading to a pneumothorax, which is an abnormal collection of air or gas in the pleural space that separates the lung from the chest wall. This condition is very painful and often interferes with normal breathing.
Another disadvantage is the ineffective delivery of medication to the patient when dispensed into the pressurized gas stream from a nebulizer or inhaler. Delivery ports for this type of application are typically set-up proximal to a ventilator. When medication in a nebulized form is dispensed in this fashion, a portion of the medication is lost as it travels through the hose before reaching the patient's nasal cavities. The greater the distance the more the prescribed dosage is diminished. In other cases, the nasal mask is removed from the patient in order to deliver the intended medication using a wall flow meter. Unfortunately, some patients can suffer from poor oxygenation during this process.
Another disadvantage is that the face-contacting portion of the mask can apply excessive pressure to the patient's face resulting in discomfort and skin irritation. Over extended periods of use, these forces can cause facial soreness and/or ulceration.
A variety of mask assemblies have been disclosed. U.S. Pat. No. 5,560,354 discloses an apparatus for use with a ventilator comprising a nose piece to lit over the patient's nose, an intake port on one side of the nosepiece comprising two soft nasal tubes connected to the ventilator, a one-way exhaust port on the other side of the nose piece and a seal about the perimeter for making a gas tight seal against the patient's face. The mask is secured to the head using a headband on which the intake and exhalation port tubes are attached. The disadvantage of this mask assembly is that it provides the pressurized gas flow directly into the nasal cavities, which can make inhalation difficult or result in barotrauma. In addition, neither the mask not the intake port provides an adapter for administering a medication in close proximity to the patient's nasal passages. This makes administration of a proscribed amount of medication difficult. Further, the nosepiece is not directly secured to the patient's face but instead relies on the connection of the flexible intake and exhaust ports to the headband for stability. This design makes it difficult to assure a gas tight seal against the patient's face.
U.S. Pat. No. 7,942,150 discloses a mask assembly for treating a patient comprising a plenum chamber, or mask, adapted to create a seal about the patient's nasal cavities, a support structure for maintaining the mask assembly in place, an exhaust vent, at least one air inlet and a baffle separating the air inlet from the exhaust vent. The disadvantage of this mask assembly is that it provides the pressurized gas flow directly into the nasal cavities. Another disadvantage is the absence of a medication delivery port in close proximity to the patient.
U.S. Pat. No. 6,615,834 discloses a device for delivering gas comprising a mask in communication with a gas supply, at least one outlet vent, a removable filter for filtering the diffusing expired gas and headgear for securing the device to the patient's head. This device suffers from similar disadvantages as those listed above. The orientation of the intake vent on the mask provides pressurized gas directly into the nasal cavities. In addition, there is no delivery port for administering a medication in close proximity to the patients nasal passages.
U.S. Pat. No. 7,913,692 discloses a CPAP mask comprising a shell or body that covers the mouth and nose, a cushion about the perimeter edge, an inlet port and a gas flow generator having a housing for maintaining an impeller to provide gas flow and a motor to drive the impeller. The flow generator is positioned below the base of the nose and delivers pressurized gas directly into the nasal cavities. The disadvantages of this system are similar to those listed above for U.S. Pat. No. 6,615,834. In addition, incorporating the gas flow generator into the mask makes it larger, heavier and more cumbersome to use.
Other patents include: U.S. Pat. No. 8,042,538 which discloses a nasal mask having a rigid body, a single intake port positioned below the nose and directed at the nasal cavities, a cushion about the perimeter edge and headgear comprising a yoke and two straps for securely affixing the mask to the patient's face; U.S. Pat. No. 7,036,508 which discloses a harness assembly adapted to secure a nasal mask to a patient's face comprising a pair of upper and lower straps and a cap portion with D-shaped coupling members for joining the upper and lower straps; and U.S. Pat. No. 8,186,348 which discloses a respiratory mask assembly that comprises a mask having a single intake port and a cushion about its perimeter edge and an adjustable forehead support for maintaining the position of the mask. These three patents demonstrate the necessity for maintaining the mask in position while creating a gas tight seal on the patient's face for efficient and effective treatment. However, the complexity of these devices make them cumbersome to wear and difficult to set-up and maintain their position during use.
Accordingly, there is a need in the field for a nasal respiratory assembly that is easy to use and is able to deliver a breathable medication to a patient both effectively and comfortably.